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ACTIVITY PROGRESS REPORT IMARPE. -WP 7. Claudia Wosnitza-Mendo Michael Ballón Carlos Benites. PERU Main distribution area of the demersal fish species. INVESTIGATED SPECIES Hake (Merluccius gayi peruanus) Lumptail searobin (Prionotus stephanophrys)
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ACTIVITY PROGRESS REPORT IMARPE. -WP 7 Claudia Wosnitza-Mendo Michael Ballón Carlos Benites
INVESTIGATED SPECIES Hake (Merluccius gayi peruanus) Lumptail searobin (Prionotus stephanophrys) Peruvian rock seabass (Paralabrax humeralis) Peruvian banded croaker (Paralonchurus peruanus)
Mean length at Maturity Hake example ( females) Maturity ogives of hake for different periods
Mean length at Maturity (hake example) Mean length of hake (Paita fleet) vs Lm 50.
Optimum length (Lopt) Croaker example Problem: different biological parameters lead to a different Lopt Lopt 29.06 Parameters: Loo to k M 50.28 -0.2533 0.23159 0.50748 Lopt 28.63 Parameters: Loo to k M 53.3 -1.661 0.137 0.35414 Lmax 65 cm
% Megaspawners croaker Lopt+10% Lopt = 32 cm
Complementary research Fish Condition and reproduction activity Long term Upward trend in condition factor Downward trend in reproduction activity Short term Negative impact of El Niño In both: Fish condition and reproduction
Papers in progress • Long-term changes in mean length at maturity of four Peruvian demersal species • Trend in relative investment of energy in growth and/or reproduction by Peruvian hake from 1972 – 2004: an issue of length dependence • Spatial separation of spawning units of hakeMerluccius gayi peruanus